arm64/hwcap: Add support for FEAT_CSSC

FEAT_CSSC adds a number of new instructions usable to optimise common short
sequences of instructions, add a hwcap indicating that the feature is
available and can be used by userspace.

Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20221017152520.1039165-2-broonie@kernel.org


Signed-off-by: Will Deacon <will@kernel.org>